The first in a series of reports from northern Nigeria by the BBC's West Africa correspondent, Mark Doyle, assessing the impact of the 11 September attacks

Inside the ancient palace of the Emir of Kano, courtiers mill about in gorgeous coloured robes. One of Africa's timeless Islamic ceremonies is taking place - the Emir of Kano is holding court.

Timeless tradition is observed

In the courtyard, camp followers sound long traditional trumpets, while others play smaller instruments made from cow horns.

We began our Nigerian journey in Kano because it is the centre of one of the great Islamic emirates of the north of the Federation. It has also been a centre for clashes between Christian and Muslims.

We wanted to see if the "War Against Terrorism" or "Jihad against America" (take your pick) had heightened those tensions.

The Emir's court was our introduction to the north.

Silent and dignified

The Emir himself, silent and dignified, made his progress to the throne. Once seated, he carefully surveyed the courtroom before him.

We totally disagree with what Osama Bin Laden is saying about mounting a Jihad

Senior Palace Counsellor

At the far end of the large but simple room, a group of petitioners lay prostrate, with their hands flat on the red carpet in front of them. These men didn't look directly at the Emir but talked through lawyers who would, in turn, interpret the Emir's subtle signals.

Everyone in the room is male.

Throughout the proceedings the Emir doesn't appear to say a word. But his decisions in the courtroom, conveyed by a nod or a sign, are passed on through the royal scribes who sit cross legged in front of him. His word will become law.

The Emir hears the petitions of his people

One petitioner has a land and cattle dispute - the Emir would investigate.

A young boy appears who is said to have killed someone - he would be taken to the police.

A third man has paid for electricity but it has not been supplied - the Emir's men promised to see government officials about it.

Vast power

The power of the Emir should not be exaggerated. In the end the secular Federal government, with its vast oil revenues, pays much of the Emir's budget.

But nevertheless the conservative Islamic power structures of northern Nigeria remain a force to be reckoned with, as they have from time immemorial.

There is much sympathy for al-Qaeda on the streets of Kano

It was into this timeless scene that 11 September exploded.

Outside the palace, in the dusty and polluted streets of Kano city, some taxi cab drivers were proudly displaying photographs of Osama Bin Laden on their windscreens.

One young man had a smaller picture of the al-Qaeda leader pasted on his motorcycle:

"I like Osama," the man explained, "because he tells the truth. No Muslim is happy with the bombing of Afghanistan".

About a month after the attacks on New York and Washington, riots broke out in Kano following an anti-US march.

The Senior Palace Counsellor, Alhaji Abbas Sanusi, agreed to speak for the Emir about 11 September and its effect on Nigeria.

'Outsiders' blamed

The October riots in Kano were, he said, a result of "misunderstandings" due to "outsiders" who created disharmony. The Senior Counsellor pointed out that non-Muslims had lived in Kano since before the Europeans arrived in 1903, and there had been peace between the various groups.

I understood the word "outsider" to be a sort of political code-word for anyone who challenged the pre-eminence of the Emir and his conservative, traditional structures - be they Christians or radical Muslims.

Alhaji Sanusi: 'Islam does not condone terrorism'

As for the dispute between Osama Bin Laden and the west, Alhaji Sanusi said: "We do not think this is a dispute between Islam and Christianity. We are following it very closely. Islam does not condone terrorism".

But he balanced this last statement, a reference to the 11 September attacks.

"We know the American position, but we also know that the Afghans say they are not terrorists... The Americans will be wrong if their struggle turns into a struggle against Islam," he said.

These carefully chosen words reflect the Emir's desire to tread a middle path between the heated anti-Americanism of the Islamic street, and the Nigerian Government's more measured tone which has to reflect the Federation's pluralism.

However, when I asked Alhaji Sanussi if the Emir agreed with Osama Bin Laden's statements that he was mounting a Jihad against America, the response was clear.

"We totally disagree with what Osama Bin Laden is saying about mounting a Jihad. It is not a Jihad. There are due processes to follow and anyone who takes a life without those processes being followed cannot be said to be mounting a Jihad."

Stoking violence

Throughout the riots of mid October, and since, there has been the usual dispute about "who started it" - the Christians or the Muslims - but there was no doubt that Afghanistan was a factor in stoking the violence.

Muslims blame the Ibos for the violence

At a row of mainly Muslim-owned, but now burnt-down shops, in central Kano's Galadima Road, a trader told me: "The Ibos did this". The Ibo ethnic group, originating in south-eastern Nigeria, is mainly Christian.

At a small church on the other side of town, now also a burnt-out wreck, a Christian elder said: "Muslim Youths attacked here and tried to kill the Pastor. They said they were reacting against the American bombing of Muslim Afghanistan".

At least 100 people were killed in the Kano clashes.

What happened in Kano was in fact more complex than at first appeared. If most Ibos in the north are Christians, then most Moslems are Hausa Fulani. Their disputes often have as much to do with, for example, land ownership or economic questions as they do with religion.

One Muslim trader in Galadima Road also pointed out: "It wasn't just the Christians who were to blame. When the trouble broke out, unemployed youths of all groups took advantage of the situation to loot and pillage".

Another major factor in the potent mix of religion, ethnicity and politics in northern Nigeria is the dispute over the introduction of Sharia, or the strict application of Koranic law which allows punishments such as amputation and stoning for certain crimes.

Next stop Kaduna

Afghanistan is a relatively recent topic of controversy and Nigerians have been killing each other over Sharia since long before 11 September.

Dr Ahmat Datti, President of the Supreme Council for Sharia in Nigeria, argues that Sharia is not being introduced but "re-introduced".

He says that when the British colonialists ceded independence, they did so on the condition that certain aspects of Sharia would not be applied.

Muslims were now simply correcting that wrong, he said.

Christians violently disagree with the introduction of Sharia, even if Islamic leaders have sought to re-assure them that it will only apply to Moslems.